This invention relates generally to fluid flow couplings and coupling assemblies for releasable interconnection of fluid flow conduits to permit sealed fluid transfer between the flow conduits. More specifically, this invention relates to an improved fluid coupling assembly designed for fluid transfer with relatively small pressure losses and with minimum or no fluid spillage upon subsequent conduit separation, wherein the coupling assembly is particularly adapted for remote control operation and further includes convenient means for manual override operation.
Fluid couplings in general are widely known for use in temporarily connecting a pair of fluid flow conduits to permit sealed fluid transfer from one flow conduit to the other. For example, such fluid couplings have been used for many years in hydraulic power systems to permit rapid connection and disconnection of two hydraulic fluid flow conduits. In addition, such fluid couplings have been used in a wide variety of other fluid transfer environments, such as, for example, in the transfer of fuels, coolants, or other fluids from one aircraft or spacecraft to another. Fluid couplings have also been used in many applications in the chemical and petroleum industries to permit fluid transfer from one vessel to another, such as transfer from a fluid storage vessel to a petroleum container or the like for shipment and/or sale.
A typical fluid coupling construction includes a pair of matingly engageable coupling members mounted respectively on two fluid flow conduits, with each coupling member having an internal valve component movable to control fluid inflow or outflow with respect to the associated flow conduit. Whenever the two coupling members are separated from one another, the respective valve components of the coupling members are normally maintained in closed positions preventing fluid loss or spillage from the flow conduits. However, when the coupling members are matingly engaged, the respective valve components are designed for movement to one positions permitting fluid flow through the connected coupling members from one flow conduit to the other. In the past, in many fluid couplings, the valve components have been spring-loaded to their normally closed positions and opening movement has occurred incident to mating engagement of the coupling members in response to abutting contact between the valve components. Subsequent valve component closure has occurred incident to separation of the coupling members permitting the springs to displace their respective valve components back toward the normally closed positions.
In fluid couplings of this general type, however, at least some fluid spillage is normally encountered each time the coupling members are engaged or separated. More particularly, movement of the coupling members toward an engaged relationship tends to result in at least partial opening of the valve components before a fully sealed coupling member engagement can be achieved, resulting in a small amount of fluid spillage to the surrounding environment. Similarly, when the coupling members are disconnected, a small quantity of fluid can escape to the environment before the spring-loaded valve components can be returned to their closed positions. Alternatively, and sometimes in addition, a small volume of residual fluid can become trapped between the valve components, wherein this residual fluid will spill to the surrounding environment upon subsequent coupling member disengagement. While minor fluid spillage may not present significant problems in some fluid transfer applications, such minor fluid spillage can be extremely undesirable and potentially hazardous in other applications, such as in the transfer of volatile or hazardous fuels or chemicals.
In some fluid coupling design, alternative valve components have been provided for opening and closure movements within associated coupling members in response to a drive input force independent of biasing springs, thereby permitting valve component opening and closure subsequent to fully sealed mating engagement between the coupling members. While such alternative designs advantageously overcome fluid spillage problems due to partial valve component opening when the coupling members are partially engaged, many such fluid couplings have not satisfactorily eliminated residual fluid volumes trapped between the valve members in the closed positions. Moreover, these and other fluid coupling designs have not provided a practical drive means for independent valve component movement adapted for remote control operation in a spacecraft environment or the like, while additionally providing a simple and easily operated manual override arrangement for redundant manual control of valve component movement.
There exists, therefore, a significant need for an improved fluid coupling assembly designed for fluid transfer between flow conduits with relatively small fluid pressure losses and with little or no fluid spillage upon subsequent conduit separation. Moreover, there exists a need for an improved coupling assembly adapted for remote control operation and including a practical manual override arrangement. The present invention fulfills these needs and provides further relates advantages.